The present disclosure relates to a micromechanical structure, in particular a micromechanical sensor arrangement, and a corresponding operating method.
Micromechanical (or MEMS) structures, in particular sensor arrangements, such as inertial sensors, for example, are produced nowadays either as discrete sensors on dedicated chips or as integrated sensors together with an associated evaluation circuit. In the case of integrated sensors, there is either a vertical integration, wherein the sensor is arranged above the evaluation circuit, or a lateral integration, wherein the sensor is arranged alongside the evaluation circuit.
DE 11 2006 000 131 T5 discloses a micromechanical structure for forming an integrated spatial light modulator, wherein the micromechanical structure is constructed directly onto a CMOS evaluation circuit. The electrodes and the wiring thereof are defined during the production process, wherein the electrodes in the MEMS part are connected by means of through-contacts to the circuit parts in the CMOS wafer.
Defining the electrode configuration during the production process results in little flexibility for optimizing the latter toward the individuality of each chip or the operating situation thereof. The individuality of each chip results from the process tolerances, for example layer thickness differences between the center of the wafer and the edge region thereof, and also local process tolerances, e.g. different widths of adjacent structures within a chip. Alongside such geometric factors, there are also other influencing factors, such as e.g. surface charges. The operating situation can change as a result of temperature influences or ageing, for example, which likewise can only be partly compensated for by adapting voltages.
The location, the geometry and the task of the electrodes cannot subsequently be changed in the known production process. Only the applied voltages can be adapted to the process tolerances. As a result, unnecessary electrodes representing a dead area may be present, or the electrodes may be too small or too large for the available voltage levels, or the electrodes may be situated at a non-optimal location.
FIGS. 2a, b are schematic illustrations of an exemplary micromechanical structure, in particular sensor arrangement, specifically FIG. 2a in plan view, FIG. 2b in perpendicular cross section along the line A-A′ in FIG. 2a. 
In FIGS. 2a, b, reference sign 1 designates a micromechanical structure in the form of an acceleration sensor. The micromechanical structure 1 has a movable MEMS element 7 in a micromechanical functional plane 100, e.g. composed of polysilicon, which is anchored by means of spring elements 2 in the functional plane 100, electrical contact elements 3 in a contact plane 300 on conductor tracks 5 in a conductor track plane 500 on an insulation layer 600, e.g. composed of oxide, and via the latter in turn to a substrate 700, e.g. a wafer substrate. Via the conductor tracks 5 and the contact/electrodes 3, an electrical potential can be applied to the movable MEMS element 7.
Situated opposite the movable MEMS element 7 are immobile MEMS stator elements 4, which are likewise anchored by means of electrical contact elements 3 in the contact plane 300 on conductor tracks 5 in the conductor track plane 500 to the substrate 700, in the functional plane 100 as counterelectrodes, which are capacitively coupled to the movable MEMS element 7 by means of a comb structure K. Via the conductor tracks 5 and the contact elements 3, an electrical potential can be applied to the MEMS stator elements 7.
Further immobile MEMS elements 7a in the functional plane 100 in interspaces Z of the movable MEMS element 7 are connected by means of contact elements 3a to the conductor tracks 5 and, as described above, anchored to the substrate 700. Via the conductor tracks 5 and the contact elements 3a, an electrical potential can be applied to the immobile MEMS elements 7a. 
By virtue of the contact elements 3 and 3a formed in this way, which are embedded for example into a sacrificial layer (not shown), and the conductor tracks 5 which lead to potential connections (likewise not illustrated), the electrode links are defined in an invariable fashion.